Right to equations one with an x intercept but no y intercept and one with a y intercept no x intercepts

Evaluate the dot product of (3,-1) and (1,5)

Quadrilateral wxyz is on a coordinate plane. segment yz is on the line x+y=7 and segment xw is on the line x+y=3. which statement proves how segments yz and xw are related

When only separate discreet points are graphed it is called?